Recently due to westernization of eating-habit and increase of social stress, the number of patients with diabetes mellitus has been significantly increasing. Diabetes mellitus is a disease as main cause of chronically hyperglycemia and presents the symptom of said disease by lack of insulin or an excess of inhibitory factor for activity of insulin. Namely, diabetes mellitus is characterized as absolute or relative lack of insulin activity. Diabetes mellitus is clinically classified into insulin-dependent diabetes mellitus (IDDM) and noninsulin-independent diabetes mellitus (NIDDM).
Therapeutic exercise or dietetic therapy is first tried for treatment of diabetes mellitus. In case that decrease of blood sugar is insufficient even by these therapies, therapy by medicine is then tried. As an oral antidiabetic agent, sulfonyl urea (SU agent) is often used. The activity of this agent is based on promotion of insulin secretion in pancreas and therefore hypoglycemia occurs as side effect. Further, it is known that secondary inactivity occurs due to exhaustion of pancreas by plenty uses of a SU agent. On the other hand, thiazolidinedione derivatives for an antidiabetic agent, which were recently found (Diabetes 2 Nihon Rinsho, 725:125–145 (1997)), was paid attention by the reason as an agent which can control blood sugar by new mechanism showing improvement effect of peripheral insulin resistance. However, liver disturbance as significant side effect was reported on these derivatives and said derivatives have a big trouble in safety.